A die bonder is an apparatus that picks a semiconductor die from a supply of semiconductor dies (e.g. a wafer tray) and places it on a semiconductor die carrier (e.g. a lead frame). Such a process is known as die bonding. The die bonder comprises two important modules: i) a bond head for transferring and bonding the semiconductor die to the semiconductor die carrier and ii) a bond stage for supporting the semiconductor die carrier during the die bonding process. To ensure the quality and reliability of the die bonding process, the bond head and the bond stage should be mutually aligned. Accordingly, the surfaces of the bond head and the bond stage facing each other should be parallel to each other before the semiconductor die carrier is placed on the bond stage for die bonding. During die bonding, a bonding surface of the semiconductor die is pressed by the bond head against the semiconductor die carrier with a designated force and under a certain temperature profile. Since the bonding surface of the semiconductor die includes many solder or gold bumps with dimensions not exceeding a few hundred microns, a small deviation of the alignment of the bond stage with respect to the bond stage (e.g. 10 microns) might result in side forces and placement error, which thereby compromises the quality and reliability of the die bonding process. Importantly thus, alignment of the bond head with respect to the bond stage should be maintained to ensure the quality and reliability of the die bonder.
Accordingly, it is an object of the present invention to seek to propose an apparatus that ensures the parallelism of the surfaces of the bond head and the bond stage facing each other, and hence, the alignment of the bond head relative to the bond stage.